Virtually all toilets have a bowl unit including a bowl, and a cover or lid which is hinged to the bowl unit for movement between a normal closed position in which the bowl is concealed by the lid, and a raised position in which the toilet can be used. Often, a separate seat is also hinged to the bowl unit inside the lid so that it too can be raised and lowered (when the lid is up).
In the case of a domestic-type toilet designed to be permanently installed in a residence, the bowl unit is normally made of vitreous china and is designed to be bolted to a floor-mounted waste outlet flange. A lid and seat, typically of plastic, are held in place by hinges that bolt to the china bowl unit rearwardly of the bowl opening. Toilets for recreational vehicles and portable toilets also usually have a hinged lid and seat. Typically, the bowl unit is a plastic moulding with integrally formed lugs behind the toilet bowl opening to which the lid and seat are coupled by hinge pins. In a portable toilet, the bowl unit will normally be a separate portable unit supported on and coupled to a holding tank when the toilet is in use. Reference may be made to U.S. Pat. Nos. 4,091,475 and 4,439,875, both assigned to Sanitation Equipment Limited for descriptions of known portable toilets.
In all of these types of toilet, the lid and seat are generally hinged to the toilet bowl by hinge pins that allow substantially free hinging movement of the lid and seat. If the lid is raised, it will generally not stay in a raised position but must be either held open or pivoted right back until it rests against other structure or a stop forming part of the hinge. The fact that the lid and seat are hinged freely is a significant disadvantage in the case of a portable toilet, since the lid and/or seat may tend to swing out from the bowl unit when the toilet is carried or transported. Where the toilet is installed in a recreational vehicle, this can make for annoying rattling or chattering of the lid when the vehicle is in motion. U. S. Pat. No. 4,589,148--assigned to Thetford Corporation discloses a toilet hinge in which the hinge pin is restrained by resilient fingers; however, the patented arrangement is apparently designed to allow the hinge pin to float vertically rather than to control hinging movement.
An object of the present invention is to provide an improved hinge arrangement for the lid and/or seat of a toilet.